What happened to Harfbuzz ?

[John Emmas <johne53 tiscali co uk>]

When I last downloaded a tarball for Pango (maybe a year or so ago) the code included some source modules for 
a library called Harfbuzz.

More recently, I downloaded Pango from Git and realised that Harbuzz isn't included any more.  I can obtain 
Harfbuzz here:-

        http://www.freedesktop.org/wiki/Software/HarfBuzz

But I just wondered why it's been removed.  Was it removed because I should now build it separately?  Or was 
it removed because it isn't needed any more?

Thanks,

John